Purification of a fully metal-depleted Cu, Zn superoxide dismutase from copper-deficient rat liver

Luisa Rossi, Eliana Marchese, Angelo De Martino, Giuseppe Rotilio, Maria R. Ciriolo

Research output: Contribution to journalArticle

Abstract

A copper-deprived form of the enzyme Cu, Zn superoxide dismutase was identified in the liver of rats made copper-deficient by dietary restriction. In homogenates of such livers Cu, Zn superoxide dismutase presents a dis-homogeneous electrophoretic profile, with respect to the native enzyme. When rat liver extracts were treated with exogenous copper an electrophoretic pattern resembling the native one was observed. Enzyme purified by chromatography on DE-52 resin shows two major components, one corresponding to genuine, native enzyme and another one, eluting at higher ionic strength. The latter protein (Fraction II) consists of several isoforms which show the same characteristics of the native superoxide dismutase as far as immunoreactivity and molecular weight are concerned, but with decreased contents of copper and zinc. Its catalytic constant, referring to copper content, was 15 times lower than that obtained for the native enzyme. Moreover, the catalytic power of purified Fraction II was not regained upon incubation with copper. The occurrence of a superoxide dismutase void of metals confirms the hypothesis that this protein plays a dual physiological role: in metal metabolism and in superoxide anion dismutation.

Original languageEnglish
Pages (from-to)257-262
Number of pages6
JournalBioMetals
Volume10
Issue number4
DOIs
Publication statusPublished - 1997

Keywords

  • Copper-deficiency
  • Purification
  • Rat liver
  • Superoxide dismutase

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)

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